Frozen Leaves – A Curiosity

Like the rest of the UK we have been experiencing extremely cold weather the last couple of days. I don’t know what the temperature went down to last night as I don’t have an outside thermometer (but its going on the Christmas list) but the temperature hasn’t risen above -5 all day. We have been lucky so far here in Worcestershire with only a dusting of snow yesterday, I am hoping it stays that way.

What has interested me is the way plants have responded to the extreme cold. The top photo is of a Japanese Holly Fern. The plant has been in situ for a couple of years and I noticed the other day how lush and healthy it was looking and how it had put on a real spurt of growth. However, this morning I was surprised at the appearance of the leaves. They were much darker, almost black, and had lost their shine and rigidity, (the shine in the photo is from the camera flash).

Just by the Japanese Holly Fern is a young Sarcococca confusa, or Christmas Box, and this has reacted in exactly the same way. Both the plants are in a fairly sheltered bed with a 4ft wall behind them and a large Rosemary bush on top of the wall providing some shelter.

Conversely, a Pelargonium that I had completely forgotten about seems to be a lot more resilient to the cold with just a frosting. I would have expected the leaves to be limp at the least.

This has bemused me all day, the fern and box are perking up a little but not much and the Pelargonium is now safely in the greenhouse. I am assuming that the reason the fern and box reacted as they have is due to the water in the leaves being frozen and I suppose that as there aren’t that many evergreens around in the garden there is little to compare them with. But why the Pelargonium didn’t react in the same way I don’t know. It was perched on top of a wall so maybe the more open site helped it in some way that is beyond me.

Anyway, it has been interesting to observe and I think some of the studying I have recently been doing about leaf structure etc has probably raised my curiosity and made me more observant of how plants are behaving. I am hopeful that once the weather warms up the plants will perk up as well.

Indeed, it is interesting as to why different plants suffer from the cold when others carry on as normal. Everything inside must be frozen regardless and thus no water/nutrient movement through capillary action, so perhaps it is down to the structure of the leaf which keeps it rigid?
Something to ask on your course at least :)

Interesting! We’ve had similar conditions here, no snow but well below zero at night, and today I noticed that the previously lush and lovely foliage on both my Aucuba japonica crassifolia and the Fatsia had done exactly the same as your Christmas box. I’m not particularly surprised by the Fatsia, but the Aucuba has never done this before. I also think I have lost any chance of my oak leaved hydrangea turning fiery colours, it too is now festooned with droopy green leaves. Will be very interested to hear if your studies come up with the answer as to why.

One of my succulents caught the October frost (-5) on one side a leaf had frozen solid like an ice cube, it died but the plant once moved inside has survived. Lots of plants droop and look sad while the frost is on them and then cheer up. Its strange to see it so cold with half the leaves still on the oak trees. Alsion lemonaday

I noticed during our cold last week how different some of the evergreen shrubs reacted and some things hardly seem to notice it at all. Most everything is back to normal now that it’s warmed back into the 40’s. It’s actually felt warm after being so cold.

We all learn from each others observations, an very though provoling post. I think the reaction from the evergreens that would usually be unaffected is the suddenness of the change in temperature. Probably the plants were still in growth mode and so full of sap; when they constrict the flow of sap, they recover. More strange is the pelegonium , but perhaps becasue it was in an open position it was already going into a domant state and so didn’t suffer. Christina

Dear Helen, It always seems to me that however hard one tries to second guess how plants may react to different weather conditions, they surprise one at every turn. I do like your Japanes Holly Fern, such elegant foliage would grace any border.

It is interesting to notice how plants respond to winter conditions. I’ve been marveling at my passion vine (which I thought would be dead by now) and it’s gone and survived 5 degree night time temperatures. Crazy. I would never have thought a pelargonium would pull thru those extremes so well!

It started to snow here for about a week now. And I was surprised to see those vines on pergolas survived below zero temperatures. Their defense mechanisms for cold weather are just unpredictably good.

This is fascinating. I’ve been watching my echiums very carefully in the recent frost and snow – they wilt so dramatically in the cold that they almost look dead and then miraculously come back to life as the temperature rises. It’s amazing to watch.

About Me

I started this blog in 2008 to record how my garden developed, it quickly became a gardening journal and I have loved it ever since. I am passionate about horticulture despite working in higher education administration. When I'm not messing around in the garden I am teaching myself embroidery.